This invention relates in general to excavator machines and, in particular, to an excavator machine especially adapted for the scraping of walls, vaults, or tunnels.
More specifically, but without restriction to the particular use which is shown and described, this invention relates to an excavating machine having an articulately mounted and angularly positionable material excavating tool mounted on the free end of a working arm of the excavator machine and adapted to absorb high stress impacts incurred during excavation.
During the excavation of material, such as encountered in clearing excavation walls, vaults, and tunnels, it is necessary to scrape the walls and ceilings of vaults and tunnels to dislodge rock or loose materials which are not solidly anchored in the surrounding ground and, therefore, present hazards to workmen. In order to loosen such material, an excavating machine is used to scrape the walls and ceilings of the vaults and tunnels and in so doing the excavator is frequently subjected to heavy impact stresses. These impact stresses frequently occur when the scraping portion, or material excavating tool, of the machine loosens material and then is abruptly propelled into the solid material from which the loosened material had become dislodged. The forces applied to the excavator from such impacts frequently are sufficient to lift the front portion of the excavator off the ground, abruptly dropping it back to the ground from the height to which the excavator has been lifted. These violent shocks cause very high stresses in all components of the excavating machine, and frequently result in breaking machine components.
In order to minimize damage to the components of the excavator from such impacts, it is desirable to absorb the impact which occurs during operation. However, the shock absorbing system must permit the material excavating tool to exert a sufficient force for dislodging loosened material. The present invention allows an excavator to function in normal working operation, but absorbs the high stress impact imparted to the working components of the excavator, and dissipates this impact to prevent structural damage to the working components or the excavator itself. While this invention is believed to have general application to any type of equipment wherein it is desirable or necessary to absorb impact loading, for convenience of illustration the preferred embodiment is described with reference to an excavator especially suitable for scraping the walls and ceilings of vaults and tunnels.